The present invention relates to improvements in wheel assemblies of the general type used with modern shopping carts and the like. More particularly, this invention relates to an improved friction wheel assembly having friction means for applying a controlled frictional resistance to wheel rotation sufficient to hold a shopping cart in place while parked yet permit the shopping cart to be rolled about substantially in a normal manner.
Shopping carts are commonly provided by supermarkets, convenience stores, and other retail establishments for use by customers to collect items for purchase and for transporting purchased items, for example, to the customer's automotive vehicle parked typically in a parking lot adjacent to the retail establishment. Such shopping carts typically comprise a metal or plastic basket supported upon a sturdy frame which is in turn supported upon a plurality of wheels for easy rolling movement. The cart design is normally intended to be pushed about by the customer with minimal physical effort yet provide a sturdy cart structure capable of withstanding customer abuse and long-term use.
In the past, shopping cart wheels have been designed for substantially free-wheeling rolling movement to minimize the physical exertion required by the customer to move the shopping cart about a store or parking lot. However, such wheel designs are disadvantageous in some circumstances. For example, such wheel designs permit the shopping cart to be displaced easily from a parked position by minor bumping or jostling as typically occurs in the course of cart loading or unloading. Moreover and perhaps more importantly, free-wheeling designs will not hold the cart in a parked position on a gentle slope or incline as encountered in many parking lots, thereby significantly increasing the difficulty of handling and unloading of purchased items therefrom.
Various brake devices have been proposed for use with shopping carts and the like for releasably locking one or more wheels against rotation to prevent undesired cart rolling movement from a parked position. Such brake devices have typically comprised a movable brake lever or similar component for clamping against the periphery of a cart wheel thereby preventing wheel rotation. While such brake devices can be effective in preventing cart movement when parked, they constitute additional mechanical devices which increase the cost of the shopping cart. Moreover, these brake device require positive customer actuation including setting and releasing which in practice is an annoyance to many customers.
There exists, therefore, a significant need for an improved yet relatively simple and cost effective wheel assembly for a shopping cart or the like, wherein the wheel assembly is designed for holding a shopping in a parked position yet permit the cart to be rolled about substantially in a normal manner, and without requiring customer actuation of any brake device. The present invention fulfills these needs and provides further related advantages.